1. Field of the Invention
The present invention relates to a semiconductor device mounting method, a semiconductor device mounting structure, an electro-optical device and an electronic device, and an electro-optical device manufacturing method, and in particular to a method for directly mounting a semiconductor device on a substrate and a semiconductor device mounting structure on a substrate.
2. Related Art
There is a method, commonly called flip-flop mounting or the like, for mounting a semiconductor device directly on a substrate. This mounting method is one in which electrodes are disposed on a semiconductor device (bare chip), wiring terminals are formed on a substrate, and the electrodes and the wiring terminals are brought into direct conductive contact without the intervention of wires or the like. In this method, electrodes having a protruding shape called “bump electrodes” are often formed on the semiconductor device, and these protruding electrodes are either directly brought into contact with the wiring terminals or brought into contact with the wiring terminals via a conductive paste or a conductive film.
As one example of the above-described semiconductor mounting structure, for example, in liquid crystal display devices that are one type of electro-optical device, there are cases where a wiring substrate such as a flexible printed circuit (FPC) is connected to a liquid crystal panel and a semiconductor device (bare chip), in which a liquid crystal drive circuit and the like are integrated, is mounted on the wiring substrate. FIG. 10 is a perspective view illustrating positional relations of a semiconductor device 130, in a case where the semiconductor device 130 is mounted on a wiring substrate 120 in such a liquid crystal display device, electrodes 131 and 135 disposed on the semiconductor device 130 and wiring terminals 121 and 125 formed on the wiring substrate 120. In this case, the electrodes 131 and 135 are respectively arranged at a predetermined pitch, and the wiring terminals 121 and 125 are arranged and formed so as to correspond to the formed pitch of the electrodes 131 and 135.
The semiconductor device 130 is mounted on the wiring substrate 120 by applying heat and pressure thereto via an anisotropic conductive film. FIG. 11 is an enlarged cross-sectional view showing detailed portions of this mounting structure. The anisotropic conductive film 133 is one where microscopic conductive particles 133a (e.g., particles where a conductive layer is formed on the surfaces of metal particles or insulating particles) are dispersed in a base material constituted by an insulating resin. The semiconductor device 130 is pressured and adhered onto the wiring substrate 120 via the anisotropic conductive film 133, and heat and pressure are applied thereto by an unillustrated pressurizing and heating head. Thus, the base material is temporarily softened and, as shown in FIG. 11, the electrodes 131 and 135 and the wiring terminals 121 and 125 are brought into conductive contact with the conductive particles sandwiched therebetween. Thereafter, the base material is hardened, whereby the state illustrated in the figure is fixed and the conductively connected state is maintained.
However, in recent years, there has been an increase in the number of terminals and intervals between the terminals are being narrowed in accompaniment with the complication of electronic circuits and improvements in the degree of integration of semiconductor devices. For example, in the aforementioned liquid crystal display devices, progress is being made in raising the fineness of displays, and color displays are becoming common even in portable small panels. Thus, the number of display pixels is increasing, the number of wiring terminals of wiring substrates and the number of electrodes of semiconductor devices are being increased in accompaniment therewith, and the intervals formed therebetween are being narrowed.
In such circumstances, it becomes difficult to sufficiently ensure the widths and intervals of the wiring terminals 121 and 125 of the wiring substrate 120 and the electrodes 131 and 135 of the semiconductor device 130. Thus, defects in the conductive contact between the wiring terminals and the electrodes, and short circuit defects between adjacent wiring terminals or electrodes increase, the reliability of conductively joined portions of the semiconductor mounting structure drops, and product yield deteriorates.
In view of this, the present invention solves these problems, and it is an object thereof to provide a new semiconductor device mounting method, a semiconductor device mounting structure, an electro-optical device and an electronic device, and an electro-optical device manufacturing method that can improve the reliability of conductively joined portions even when the numbers of wiring terminals and electrodes are increased and intervals therebetween are narrowed.